Peak Tq vs Peak Boost
06-09-2005, 07:42 PM
#1
Three Wheelin'
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Peak Tq vs Peak Boost
I've never had my car on a dyno, but have been looking at other guys dyno charts and I was wondering...
In most cases, is Peak TQ at the same RPM as Peak Boost Pressure ??
In most cases, is Peak TQ at the same RPM as Peak Boost Pressure ??
06-09-2005, 08:22 PM
#2
Three Wheelin'
Peak torque is a function of both volumetric efficiency of the engine and boost. On a stock 951, peak VE occurs about 3,500 rpm. This value may move higher due to breathing improvements (intake, porting, exhaust, etc.) If the turbo is spooled to its maximum boost, then peak torque occurs at about 3,500 rpm. Above 3,500 rpm torque slowly decreases as boost remains constant but VE declines.
A large turbo or high boost, however, may result in maximum boost pressure being reached at a higher rpm. The rpm when boost first hits maximum is then where the torque peak occurs.
A large turbo or high boost, however, may result in maximum boost pressure being reached at a higher rpm. The rpm when boost first hits maximum is then where the torque peak occurs.
